Plansifters



Oct. 25, 1960 J. 5. BALL ETA].

PLANSIFTERS 4 Sheets-Sheet 1 Filed Nov. 4, 1958 Oct. 25, 19

Filed Nov. 4, 195

J. 5. BALL :r

PLANSIFTERS 4 heets-Sheet 2 Oct. 25, 1960 J. 5. BALL ETAL 2,957,578

PLANSIFTERS Filed Nov. 4, 1958 4 Sheets-Sheet 5 Oct. 25, 1960 J. 5. BALLETAL 2,957,578

PLANSIFTERS 4 Sheets-Sheet 4 Filed Nov. 4, 1958 United States PatentPLANSIFTERS John S. Ball, Davenport, Stockport, and Harry Pickup,Wilmslow, England, assignors to Henry Simon Limited, Stockport, England,a British company Filed Nov. 4, 1958, Ser. No. 771,756

Claims priority, application Great Britain Nov. 11, 1957 p 4 Claims.(Cl. 209370) This invention relates to plansifters used for classifyingflour mill stock and particularly to the type of plansifter wherein aplurality of sieve units, each comprising a horizontal screen throughwhich materials of less than a predetermined size can pass and a trayelement on which the throughs from the screen are collected, both screenand tray being mounted in a framework having a plurality of verticalchannels into which the classified materials can be directed inaccordance with a predetermined scheme, are superimposed one uponanother in an enclosed group in such a manner as to ensure that thevertical channels in the frame-works of adjacent sieve unit-s coincideto form continuous channels through which classified materials ormaterials for classification can be transferred from a higher sieve unitto any lower sieve unit or to channels leading to outlet ports from thegroup enclosure. In such pl-ansifters clamping means are provided tohold the channel-forming sieve unit frameworks in close engagement witheach other and with channel elements of the enclosure means so as toprevent the leakage of any material from its predetermined channel. Itis essential that such clamping means be capable of preventing relativemovement between any of the sieve units in a group and between any partof the group and associated enclosure members Where damage to or wear onthe engaging surfaces of the parts which form the channels cIould leadto the development of leakages. Further, in view of the continuousnature of the processes on which such machines are normally employed, itis desirable that the clamping means referred to shall be rapidlyoperable w: permit sieve units to be freed for repair, rearrangemerit,or replacement in the shortest possible time. It is :also desirable thatsuch clamping and locking means shall be easily cleanable and shall notprovide inaccessible pockets in the structure wherein material beingprocessed can lodge and deteriorate to become a possible source ofcontamination or microbian infestation.

The object of this invention is to provide in plansifters of the typereferred to, improved sieve unit clamping means having the desirablefeatures described.

In accordance with this invention, each of a plurality of sieve unitssuperimposed one upon another in a group contained within a box-likeenclosure of substantially rectangular prismatic form having in onevertical side 'a'n'access opening of such size as to permit of the groupof sieve units being passed horizontally therethrough, and located atthe corner extremities of each sieve unit in a leak-proof manner byvertical extensions of the walls of the enclosure, arranged so thatsealed continuous channels which may be used as material transfer ductsare formed between the vertical outer faces of all the sieve units,in'the group and the vertical walls of the enclosure, is clampedlaterally in its location means by clamping members which may serve allsieve units in a group and which arehingeably mounted on vertical pivotsat the location extensions of the enclosure walls flanking the accessopening and provided with pivotally mounted interconnecting tie-rodsarranged so that when the tie-rod adjustment nuts are tightened pressurefaces of the clamping members are brought to bear on adjacent cornerextremities of the sieve unit in such a way as to hold it firmly inposition, the pressure applied by the interconnected clamping membersbeing equalized by a turning action of the associated members about thehinge and tie rod pivots, which latter are arranged to provide that whentension is removed from the tie-rod assemblies they may be uncoupledfrom the clamping members which can then either be hinged clear of theaccess opening to afford unrestricted access to the sieve-units or belifted vertically off their hinge pivots to facilitate cleaningoperations.

Preferably all sieve units in a group located in the manner describedare clamped towards the base of the enclosure structure by clampingmeans comprising a supporting linkage pivotally mounted from theenclosure structure and arranged to hinge up or down under the controlof a manually operable jack-screw element of the enclosure structure,and a clamping frame pivotally suspended from the supporting linkage andarranged so that pressure applied to it by cam-surfaces of the saidlinkage are transmitted by leakage sealing extensions of the frame tothe vertical walls of the channels formed in the sieve unit frameworks,the said clamping frame having ports and ducts whereby materials forprocessing passing through inlet spouts of the enclosure are transferredto the topmost sieve or to the vertical channels in the framework of thesieve units and also having rapidly removable attachment means at itspivotal suspensions so that the complete frame may be quickly removed tofacilitate cleaning.

The sieve unit corner extremities which engage the 10- cating meansdescribed may have projecting surfaces (which may be in the form ofmetal or other corner reinforcements) extending over the area of thesieve framework which contacts the leakproof seals of the location meansso that except when a sieve unit is in position to be clamped it can bemoved freely without risk of damage to the sealing means.

One form of the present invention is shown, by way of example, in theaccompanying drawings, in which:

Figure 1 is a perspective view of a six-group plansifter with two doorsfor the access opening to one of the groups and one door for anothergroup removed to show the clamping members and tie-rod assemblies inclamping position.

Figure 2(a) is a perspective view to show the method of locating andclamp-ing a sieve unit in its enclosure structure.

Figure 2(b) shows one of the clamping members in the open position.

Figure 3 is an enlarged view of Figure 1 showing the method of removingtie-rod assemblies and clamping members.

Figure 4 is a perspective view of part of one enclosure structure toshow the means for clamping sieve units towards the base thereof.

Referring to Figure l, the plansifter of basically known form comprisesa cabinet 1 housing six groups of sieve units 2. The cabinet 1 issuspended from roof members 3 by four sets of canes 4 and is caused todescribe a gyratory motion by rotation of an eccentric weight (notshown) carried on a shaft 5 and driven by a motor 6 through belts 7.Stock to be sieved enters the top of the plansifter through ducts 8 andthe sieved and classified stock leaves the bottom by the flexible ducts9.

Three of the removable doors 10 are shown removed to expose the accessopenings through which the sieve units may be removed and replaced.

Clamping means for each group of sieves is similar and that for one ofthe groups is shown in more detail in Figures 2(a), 2(b) and 3. Eachgroup is contained within a box-like enclosure 11 having in one side theaccess opening through which the sieve units 2 may pass horizontally.The units 2 are located. in the enclosure 11 in a leak proof manner byvertical corner extensions 12 and 12a of the rear Walls of the enclosureand by vertical extensions 13 of the side walls of the enclosureflanking the access opening. The units 2 are clamped laterally againstthe extensions 12:! and between extensions 12 and 13 by two clampingmembers 14 which serve half the sieve units in the group and which arehingeably mounted on vertical pivots 15 carried by bracket extensions15a of the extensions 13 flanking the access opening. The clampingmembers 14 are drawn together by two inter-connecting tie-rods 16 whichpivotally engage claw members 17 on the clamping members 14 and arearranged so that when the tie-rods adjustment nuts 36 are tightened,pressure faces 18 of the clamping members 14 are brought to bear on thesieve units so as to hold them in position, the pressure applied by theclamping members 14 being equalised by a turning action about the hingeand tie-rod pivots. When the tie-rods 16 are slackened they may beuncoupled from the clamping members 14 which can then either be hingedclear of the access opening as shown in Figure 2(b), to affordunrestricted access to the sieve units or be lifted vertically off thehinge pivots 15, as shown in Figure 3, to facilitate cleaningoperations.

Vertical channels indicated at X are formed by the sieve units, somewithin the units and some between the units and the enclosure. To assistin making each channel of the channels between the units and theenclosure proof against leakage the vertical extensions 12, 12a and 13are provided over the whole of their sieve-engaging surfaces with stripsof resilient material 37 and 38 which, when the units are clamped inposition, are compressed between the associated extensions and theengaging surfaces of the units thus providing leakproof joints betweenthe units and the extensions. To avoid damaging these seals whenremoving or replacing sieve units the corners of the units which engagethe seals have projecting surfaces in the form of metal reinforcements19. Thus except when a sieve unit is in position to be clamped it can bemoved freely without risk of damage to the leakproof sealing.

Referring to Figure 4, all the sieve units in a group, after beingclamped laterally as already described, are clamped towards the base ofthe plansifter by a clamping means comprising a supporting linkage 20,arcuateended extensions 39 of which are housed in a channelshaped member40 of the enclosure 11 in such a way that upper and lower peripheralextremities of the said arcuate-ended extensions in association with theupper and lower webs of the said channel-shaped member provide floatingpivot means about which the said linkage is arranged to hinge verticallyunder the control of a manually operated jack-screw 21 which is axiallyfixed but freely rotatable in pivoting crossbar 21a of the supportinglinkage, the said jack-screw being in screwed association with athreaded member 22 secured to the top plate 23 which forms a fixed partof the enclosure. The clamping means also comprises a clamping frame 24freely suspended on two screwed members 41 from tapped extensions 42 ofthe supporting linkage and arranged so that when the linkage 20 ispivoted downwards by the screwing-in of the jack-screw 21, the clampingframe 24 is lowered into association with the top sieve unit andthereafter pressure applied to it by pressure surfaces 25 on linkages 20are transmitted by leakage sealing extensions 26 to the vertical wallsof the channels X formed in the sieve units 2. The clamping frame hasports 27 and ducts .within it so that stock for processing passingthrough inlet spouts of the enclosure is transferred to the screen 2s oftopmost sieve unit and/ or to vertical channels in the sieve group.

The screwed members 41 are provided with sealing pads 43 which areretained in position by springs 44 to prevent material leakage by way ofthe holes in the clamping frame through which the screwed members ass.

p Removal of the clamping frame 24 and the supporting linkage 20 fromthe enclosure 11 for cleaning purposes is efiected by unscrewing the twoscrewed members 41 so that the clamping frame can be disengaged andlowered away from the linkage which can then be disconnected from thejack-screw 21 and drawn clear of the locating channel member 40.

What is claimedis:

1. A plansifter comprising a plurality of sieve units superimposed oneupon another in a group contained within a rectangular box-likeenclosure having in one vertical side an access opening to permit of thegroup sieve units being passed horizontally therethrough, said sieveunits being clamped laterally by clamping members which may serve allsieve units in a group and which are hingeably mounted on verticalpivots at the enclosure walls flanking the access opening and providedwith pivotally mounted interconnecting tie-rods, tightening means forsaid tie-rods arranged so that when tightened pressure faces of theclamping members are brought to bear on adjacent corner extremities ofthe sieve units in such a way as to hold them firmly in place, thepressure applied by the interconnected clamping members being equalisedby a turning action of the associated members about the hinge andtie-rod pivots, which latter are arranged to provide that when tensionis removed from the tie-rods they may be uncoupled from the clampingmembers which can then either be hinged clear of the access opening toafford unrestricted access to the sieve units or be lifted verticallyoif their ringe pivots to facili-r tate cleaning.

2. A plansifter as claimed in claim 1 wherein the sieve units arelocated in the enclosure by vertical extensions of the wallsof theenclosure arranged with leak proof seals consisting of strips ofresilient material covering the whole surface of those parts of the saidextensions which engage the sieve units so that sealed continuouschannels which may be used as material transfer ducts, are formedbetween the vertical outer faces of all the sieve units in the group andthe vertical walls of the enclosure.

3. A plansifter as claimed. in claim 2 wherein all sieve units in agroup are clamped towards the base of the enclosure by clamping meanscomprising a supporting linkage pivotally mounted from the enclosure andarranged to hinge up or down under the control of a manually operablejack-screw supported in the top of the enclosure, and a clamping framefreely suppended from the supporting linkage and arranged so thatpressure applied to it by cam surfaces of said linkage are transmittedby leakage sealing extensions of the frame to the vertical walls ofchannels formed in and by the sieve unit frameworks, said clampingmember, having ports and ducts whereby material for processing istransferred to the topmost sieve unit or to the vertical channels andalso having removable attachment means at its points of suspension sothat the complete frame may be quickly removed to facilitate cleaning.

4. A plansifter as claimed in claim 2 wherein the sieve unit cornerextremities which engage the locating means formed by the verticalextensions of the walls of the enclosure and their associated leak-proofseals, have projecting surfaces extending over the area of the sieveunit which contacts the said leakproof seals so that except when a sieveunit is in position to be clamped it can be moved freely without risk ofdamage to the seals.

References Cited in the file of this patent UNITED STATES PATENTS2,500,966 Thompson Mar. 21, 1950

